ROBOTICS

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Transcript of ROBOTICS

Basic ClassificationROBOTICSAccording to you which of these tasks can a Robot do?Wake you up at 5am for the PT class?YESS!!Shuffle your music player according to your mood?YESS!!Clean your filthy hostel room?YESS!!Do your ED assignments on its own?Probably not yet!A Robot mainly has two important partsThe Brain. The BodyCan take Decisions?Autonomous ManualProcesses involved?Sensing the line.Processing the informationControlling the MotorsRemembering the pathProcesses Involved?Controlling the Motors by the user.Nothing else!No programming required.Very few or no sensors required.No Brain on the BOT.Whole processing is done by the person controlling the robotThe bot is completely independent.Whole processing is done by the processors mounted on the robot.Previously -programmed to complete its tasks.Involves sensors and complex circuitry.We will look in detail about the brain part in future lectures.We have to have the mechanical and electrical part fixed before we can even think of programming.To build any bot, u need components motors, batteries, sensors, controllers, switches,etc.these are important but do not worry about them too much, lets have a fast walk through all these different components.

MOTORSMotors are responsible for almost all sorts of movements taking place in the Robots.We decide whether to use a certain motor for a certain job based on these specifications:1) RPM2) Torque3) WeightThere are more terms on this list but on the beginner’s level, this much is fair enough.

These are the simplest type of all the motors.Two pins for power supply.Reversed direction of rotation with reversed polarity.Mostly used for locomotion of the bot.Gearbox assembly is required to decrease the rpm and increase the torque.

DC MotorsServo MotorsServo refers to an error sensing feedback control which is used to correct the performance of a system.Servo Motors are DC motors equipped with a servo mechanism for precise control of angular position.The RC servo motors usually have a rotation limit from 180° to 360°.The Servos are used for precision positioning.

ApplicationsStepper MotorsA stepper motor (or step motor) is a brush less DC electric motor that can divide a full rotation into a large number of steps.They turn into integral number of steps.Stepper motors are used in floppy disk drives, computer printers, plotters, slot machines, image scanners, compact disc drives etc.

Laptop FansQuadcoptersApplicationsPrinciple of GearsSuppose gear ‘A’ has 10 teeth and gear ‘B’ has 30 teeth.Its obvious that linear velocity at the point of contact is same for both the gears.Simple calculation gives: rpm of ‘A’ = 3 X rpm of ‘B’ torque of ‘B’ = 3 X torque of ‘A’

BATwo meshing gears transmittingrotational motion. Note that thesmaller gear is rotating faster. Although the larger gear isrotating less quickly, its torque is proportionally greater. One subtlety of this particular arrangement is that the linear speed at the rim is the same on both gears.

BatteriesThe batteries provide power required to run the motors and other components on the robots.The type of battery required is decided based upon: 1) Current required 2) Weight constraints 3) Total energy required in one run of the bot

Lithium-Polymer (Li-Po)The Li – ions required for working for this cell is stored in a polymer matrix instead of a solvent.They don’t need a metal casing.Relatively lighter.Used in flying robots like quad rotors.Chargeable through 220V AC supplyHigh Price

WorkingBump Switch/ Bump SensorSensorsA robo gets to know about the surroundings through sensors, same as what we use our sense organs for.Ping SensorUses ultrasonic sound waves to measure distanceProximity sensorA proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact.

Infrared Sensors These sensors radiate in infrared region and then calculate the amount of reflected radiationIR sensor Array TSOPReceiverEmittersMiscellaneousTemperature SensorGives voltage output proportional to the temperature in degree centigradeMoisture sensorHumidity sensorLeap motion sensorAdvanced SensorsKinectImportant IC'sMotor Driver (eg.L293D)It’s a device or circuit that is essentially current amplifier; the function of which is to take a low-current control signal, and turn it into a proportionally higher-current power source that can drive a motor.

Voltage RegulatorsUsed to step down voltagesMicro-controllersThe processing units a.k.a. BRAINMechanisms InvolvedDifferential DriveDifferential drive is a method of controlling a vehicle’s motion by bringing a difference in the speeds of its wheels.